From U.S. Pat. No. 5,984,216 there is known a crushing machine including a closed crushing chamber where the chamber wall is provided with a feeding slot for glass and a discharge opening for crushed glass and comminuted plastic film. The crushing chamber includes a rotary shaft extending through the crushing chamber and driven by a motor outside the crushing chamber, where the shaft is provided with pivoting beaters or hammers distributed along the shaft inside the crushing chamber.
The prior art crushing machine is intended for manual feeding of single layers of laminated glass between two parallel rollers disposed horizontally opposite the rotary shaft. The rollers are powered by a motor and suspended by springs so that they are pre-stressed to bear against each other and may yield, so that by their movement and by friction action caused by the squeezing between the rollers, a laminated glass pane can be drawn into the crushing chamber. Immediately within the feeding slot and the rollers in the crushing chamber there is provided a supporting retainer in the shape of a steel bar which is parallel with the shaft and upon which the glass layer is supported and slides across, until the glass is hit by the hammers which by the rotation of the shaft strikes the edge of the glass laminate projecting beyond the steel bar. The glass is thereby broken into small pieces and separated from the plastic film. The chamber is substantially rectangular and has no other measures for enhancing the crushing process, and the comminuting of the glass laminate as such is effected by breaking on the transverse steel bar. The material thus comminuted, consisting of glass as well as plastic, is now conducted out through the bottom of the chamber by the action of gravity, where a vibrating sieve is provided that lets the glass pieces pass through to an underlying container while plastic pieces are conducted to another container at the side.
The crushing machine disclosed in the US patent is intended for comminuting a single laminated pane at a time by manual operation. Practical embodiments of this crushing machine made by the firm Andela Tool & Machine Inc., USA, appear to require subsequent comminuting operations with other crushing apparatuses in order to attain sufficient comminution of glass and plastic. Besides, U.S. Pat. No. 5,984,216 mentions the existence of other crushing machines with much greater capacity, but without describing their design or operation.
Furthermore, a crushing machine of the kind mentioned in the introduction is known from U.S. Pat. No. 5,505,390. This machine has a feeding slot and a discharge opening with fixed width. Here, it is difficult to achieve an efficient and simple collecting of comminuted material in the form of glass particles and pieces of plastic film from the discharge opening.